Color photography



Patented Mar. 10, 1942 UNITED STATES PATENT OFFICE 2,276,254 coLon rno'roonsrn Karl Schinzel, Zurich, Switzerland No Drawing. Application June 14, 1940, Serial 9 Claims.

This invention relates to improvements in color photography.

In the known method of producing colored images by color coupling, a silver salt is developed in the presence of a coupling component whereby a colored compound is formed where the silver develops. The coupling developing agents generally used in such a method are p-arylenediamines such asymmetrical p-amino-dimethylaniline or p-aminophenols such as dichlor-paminophenol. The coupling components, namely, phenols, naphthols, alkyl or aryl sulphonylarylamides, arylamines or acid methylene compounds may be present in the developer, or may be incorporated in the emulsion or in a layer contiguous therewith either directly or as insoluble or high molecular not diffusing compounds or in the form of insoluble salt's (see my U. S. Patent specification Serial No. 151,811, filed July 3, 1937) The resulting coupled products, e. g. indophenols, indamines or azomethines, can be split in the cold by the action of a 1% to'5% solution of acid, liberating a quinone which remains in the position in which it is formed if it is insoluble or sufliciently high-molecular. The present invention is based on the discovery that a quinone, such as one produced from an indophenol, when present in a photographic emulsion, e. g. a silver halide emulsion layer, can combine at ordinary or slightly raised temperatures with phenylhydrazine or with its substitution products or similarly-acting compounds under neutral or weaklyacid conditions to give a colored azo compound (or hydrazone). Such a compound is usually more resistant to acid than the coupled product from which the quinone may have been formed.

In carrying out the present invention a colored insoluble quinone or similar compound which may be obtained by hydrolysis of a coupled dye in a photographic emulsion is treated with an arylhydrazine or arylhydrazide to produce a colored dye or arylhydrazone. Such quinone dye or the like may be one which has been produced durin photographic development of a silver salt image in the photographic emulsion. If the quinone group will only react with difflculty with an arylhydrazine r arylhydrazide then one may employ a quinone which contains an aldehyde or ketonicgroup. In such a case an arylhydrazine or arylhydrazide which react with said aldehyde or ketonic group in the quinone or the like present in the photographic emulsion to produce a colored azo dye or arylhydrazone.

The process of the present invention is especially useful in connection with color photo- In Great Britain June 16, 1939 graphic processes employing coupling development since the dye obtained on coupling can be split by dilute acid leaving the qjuinone in the gelatine in a highly-dispersed form, or in pseudo solution within the gelatine. The sulphonylimino-quinones formed when sulphonarylamides are used as the coupling components, as well as carbonyl compounds such as ketones, e. g. the p-diketones formed when acyloacetic derivatives are used as the coupling components, are included within the term quinone since they are capable of reacting similarly with solutions of the arylhydrazines, their substitution products and similarly-acting compounds with formation of azo dyes or hydrazones.

The liberation of the quinone from the coupled product and the combination of the arylhydrazine therewith can in many cases be effected with a single solution containing, for example 1 to 3% of a mineral acid and 1 to 5% of a soluble I salt of the arylhydrazine.

If there are present any filter dyestufis which (or whose decomposition products) will react with the arylhydrazine, such filter dyestuffs should be removed 'or decomposed and. their decomposition products if necessary washedout before subjecting the emulsion to the action of the arylhydrazine.

In choosing the hydrazine to be employed in any particular case, regard must be had to the nature of the qulnone. Thus, phenylhydrazine may be employed for reaction with 1:2- or. 1:4- naphthoquinone, with 1:2- or 1:4-anthraquinone as well as with similar high molecular or substituted quinones, e. g. with a-naphthoquinone substituted in the 2-position by a tetramethyldiaminodiphenylmethane group.

In some cases, i. e. with simple quinones such as benzoquinone, phenylhydrazine acts as a reducing agent. Therefore, in general, instead of using a simple phenylhydrazine, it is preferable to use arylhydrazines containing in the 0- or pposition a strong negative substituent for example a nitro group or a sulphonic acid group or a sulphamide group (see German Patent specification No. 404,647) or a halogen atom or a carboxylic acid group, e. g. 2- or 4-hydrazinobenzoic acid. Moreover, it is desirable to have, in one or more other positions in the molecule, a substituent such as a halogen atom or a sulphonic acid group.

If the hydrazine of diphenyl (Cs.H5.Ce.H4.NH.NHz) is used, it may have a hydroxyl or an amino group in the nucleus not attached to nitrogen; such amino group may be substituted by a hydroxyethyl group yielding for example NH2NH.C6H4.C6H4.NH.CH2CH2OH. One may use similar derivatives of other aryl hydrazines, such as naphthyl hydrazine. hTe salts of the or pnitrophenyl hydrazines may be used, or the salts of nitrated higher homologues and derivatives, which higher homologues and derivatives include Dhenylene dihydrazines, diphenylene-dihydrazines, diphenyl-methanedihydrazines, 3:5-bisphenylhydrazinophenol, fuchsintrihydrazine, or other hydrazines mentioned in British patent, No. 503,941, accepted April 11, 1939, provided that the salts oi the nitrated products are sufliciently water-soluble.

Furthermore, diphenylhydrazine (Cal-I5) 2H.NH2, the hydrazines and dihydrazines of anthraquinones and their leuco forms, hydrazines derived from fluorene, from dehydrothiotoluidine or from primuline base, other aromatic hydrazines, heterocyclic hydrazines, aliphatic hydrazines or the asymmetrical acylor arylor alkyl-derivatives of these, any of which may contain substituents;

e. g. nitro groups or sulphonic groups, sulphamido groups or halogen atoms, may be employed in the invention.

Aliphatic, aromatic or heterocyclic hydrazides, such as benzoyl hydrazide, .phenylcarbamide acid hydrazide, cyanuric trihydrazide or benzenesulphonic hydrazide (CsH5.SO2NH.NH2) can also be used.

The hydrazines of leuco-dyes may also be used, for example the hydrazine from m-aminomalachite green, or the hydrazines prepared from the leuco sulphuric esters of amino-thioindigo or 2-amino-anthraquinone.

The invention can be applied to photographic images comprising quinones which have been formed from coupling components from highmolecular or highly-polymeric residues (see my U. S. application Serial No. 151,811) and then non-diffusing azo dyes or hydrazones can result, even if the arylhydrazine contains solubilizing carboxyl groups, sulphonic acid groups, or sulphonamide groups.

The quinone may contain one or more substituents such as alkyl groups, acyl groups, aryl groups, arylamino groups, or acylamino groups. If the solubility of the aryl hydrazines or acylhydrazines is small, it may be necessary to accelerate the reaction by heating to 60-'70 C. or by using alcoholic or aqueous alcoholic solutions. Obviously in the first case the gelatine layers should be suitably hardened. For printing purposes one may use a colloid other than gelatine as a binder for the silver halide, for example polymerized vinyl esters or hydrolyzed cellulose esters and in this case there is less risk or the high-molecular quinones dissolving or diffusing.

When the hydrazine is used in the process of the present invention in the form of its N-sulphonic acid derivative, it is usually necessary to work at an elevated temperature to split off the SOaH group.

It the coupling components contain basic substituents, such as amino groups or quaternary ammonium groups, the splitting by acid and combination with the arylhydrazine should be effected in the presence of phosphotungstic acid or its salts or a similar heteropoly acid or its salts.

An example of the application of the invention to the production 01' natural colored pictures is as follows:

For the cyan (i. e. blue-green) image there is added to the red sensitive emulsion approximately 15 grams of a-naphthol-2-carbonic acid naphthalide or a lauryl derivative thereof per litre of emulsion. For the magenta image there is added to the green sensitive emulsion approximately 10 grams of p-naphthol-3-carboxylic acid cerylamide per litre. For the yellow image there is added to the blue sensitive emulsion approximately 15 grams of either (a) the product of condensation of salicylic acid chloride with cholestylamine or other high-molecular amine or with benzidine, dianisidine or (b) a phenol or an aminophenol substituted by a ceryl group. After development of the latent images with a noncoupling developer, the residual silver halide is developed with a coupling developer, such as one containing p-amino-dimethylaniline as the developing agent. This results in the production or images in incorrect colors. By treatment of these images with a solution of a, salt of 0- or p-nitrophenylhydrazine in 2% aqueous hydrochloric acid, the images are converted into azo dye images approaching a correct color rendering.

In another example, there may be added to the red-sensitive emulsion 8-stearylamino-anaphthol or its 3- or fi-sulphonic acid, to the green-sensitive emulsion the stearoylamide of pnaphthol-S-carboxylic .acid or 4-stearoylaminoa-naphthol or 4-stearoylamino-p-naphthol or the l-sulphonic acid of the latter, and to the not specially color sensitized emulsion 1-phenyl-3- stearyl-5-pyrazolone. After coupling development and acid hydrolysis the resulting quinones will react with dihydrazine of benzidine or 01 a nitrobenzidine to give the required complementary colors.

For pictures on paper the quantity of the components should usually be reduced to half or less.

When a coupling component is incorporated in an emulsion for the production of a quinone, it is preferably used in a form in which it is substantially non-'difiusing. Thus, phenols or naphthols may be used in the free state if they are insoluble; otherwise they may be used in the form of their insoluble salts. Alternatively, the coupling components may be used in the form of their insoluble sulphonic acids or carboxyiic acids, or sulphonic'acid amides it they .are sumciently high-molecular to be insoluble in this form; alternatively, the pseudo soluble salts of these acids with inorganic or simple organic bases such as caustic alkalis, ammonia, or -monoor dior triethanolamine, ethylene diamine or piperidine may be used, or the insoluble salts of these acids with inorganic or high-molecular organic bases, diphenylguanidine, or quaternary heterocyclic bases may be used.

However, it is to be understood that the invention is also applicable in cases where the original coupling components were contained in the coupling developer, see for example Mannes and Godowsky U. S. Patent 2,113,329, granted April 5, 1938, my U. S. Patents 2,231,684, granted February 11, 1941, and 2,172,262, granted September 5, 1939, my U. S. application Serial No. 244,655, filed December 8, 1938, and Mannes, Godowsky and Wilder U. S. application Serial No. 185,700, filed January 19, 1938. The quinone is not necessarily generated by splitting a coupled dyestufl, but may be obtained directly in development, for example by employing the developing agents described and claimed in British Patent specification No. 498,869, accepted January 10, 1939.

The present invention may be applied also to the treatment of dye images composed of the coupled products obtained by photographic development with coupling developing agents such as p-aminodimethylaniline in presence of coupling components containing reactive methylene groups such as nitrobenzyl cyanide, dinitrophenylacetic acid anilide or the dianilides or anilidoesters of malonic acid and similar compounds as described in U. S. Patent 2,186,735, granted January 9, 1940, or of sulphoacetic acid (Ber. 72/575) or of methionic acid. It is noteworthy that the azomethines of acetylacetone, acetoacetic anilide and similar coupling components are decomposed by acids to polyketones which by condensation with two molecules of phenylhydrazine yield yellow arylhydrazones. Of great practical interest are the yellow dyestuffs fast to light which are got in the same way from phenylmethyl pyrazolones or from the diand tri-arylalkylpyrazolones mentioned in British Patent specification No. 503,941 or from similar coupling components. Of course, if such compounds are to be incorporated in the emulsions, they must be used in the form of their insoluble or non-diffusing high molecular derivatives.

The coupling components described in- Schneider and Loleit U. S. Patent 2,154,918, granted April 18, 1939, having an acid methylene group attached to the nitrogen atom of a pyridine ring may also be employed in the present invention to produce the B-diketone which is reacted with an arylhydrazine.

If dinitrotoluene or the heterocyclic compounds described in Schneider and Loleit U. S. Patent 2,186,736, granted January 9, 1940, containing a reactive methylene group are used as coupling components the aldehydes formed by said splitor the original coupling components contain com-- plex forming groups for example the biguanido group, or an ortho-hydroxy or a mercapto group, or an azole ring, or an imidazole ring, or the ,orthohydroxyquinoline group, or the salicylic acid group, they can be converted into the corresponding complex salts by additional treatment with solutions of metal salts. If the final dyestuff contains basic groups as for example dimethylamino, methylamino, or amino groups, then it is possible to obtain better fastness to light by adidtional treatment with phosphotungstic salts or similar complex inorganic compounds either under neutral or acid conditions.

Numerous variations of the processes previously described are possible. The azomethines, and especially those containing an acetonitrile group, being considerably more stable to dilute acids than indophenols, or indamines, one is able to split an indophenol image in one emulsion by acid of low concentration and to convert it into the corresponding azo dyestufi image, for example the blue image, without afiecting an azomethine dye image in another emulsion on the ting yield colored hydrazones by treatment with v phenylhydrazine.

It should be understood that instead of arylhydrazines, their e-alkyl or e-acyl derivatives such as asymmetrical benzoylphenylhydrazine, or hydrazides as for example benzoylhydrazide or hippurylhydrazide may be used.

Among the coupling developing agents which may be used, there may be mentioned the arylsulphonyl or alkyl-sulphonyl derivatives of para arylene diamines.

The 4-arylamino derivatives of the 2-hydroxya-naphthoquinones. such as of the kind which are formed during development of the latent image with l:2-dihydroxynaphthalene-4-sulphonic acid or 1:2-dihydroxynaphthalene-i-carbonic acid in neutral or weak alkaline solution in the presence of aromatic amines (see my U. S. application Serial No. 151,811) generally require heating to hydrolyse them with acids. Instead of forming an azo dye by condensation of the resulting quinone with phenylhydrazine or its nitro derivatives, the same dye can be directly obtained if the development with 1:2-dihydroxynaphthalene-e-sulphonic acid or its 3-chlor derivative is carried out in the presence of an aryl hydrazine. In this modification of the invention it may be considered that the aryl hydrazine reacts with the quinone at the moment of formation of the latter. alkali the resulting red azo dyes can be oxidized by air or other oxidizing agents such as potassium ferricyanide to yellow quinone azo dyes. In such a case, it is desirable that the azo dye conta ns a high-molecular substituent to render it nondifiusing in such alkali. For coupling development also N-sulphonyl derivatives of the 4-sulphonic acids or 4-carboxylic acids of Z-aminoa-naphthol and l-amino-fl-naphthol, as also the NN-disulphonyl derivatives of 1:2-naphthal- In the presence of .same support.

Furthermore, the indophenols obtained from B-naphthol are less resistant to acids than those obtained from e-naphthol or from halogenated u-naphthol or from halogenated phenols, or the azomethines. One may, therefore, treat an element having three layers superimposed on a single support and which contains different coupling components with acid baths of successively increasing concentration. The lowest layer may contain an u-naphthol, the middle layer a B-naphthol and the top layer an acetoacetic derivative or a halogenated phenol.

On treatment with dilute or weak acids the coupled product obtained from the B-naphthol in the middle layer is split and gives a magenta image by the action of phenylhydrazine.v By the use of stronger or more concentrated acid the blue a-indonaphthol in the bottom layer is split and converted into a blue-green azodyestufi image. Finally, the coupled product in the top layer, obtained from the halogenated phenol or from the acid methylene compound is decomposed by still stronger or more concentrated acid and the yellow partial image is obtained by the action of nitrophenylhydrazine. It is not necessary to convert the images obtained by coupling development into the corresponding azo dyestufi images in all the emulsions; those in one or two emulsions may be treated. This step wise conversion of the individual images allows of the use of difierent hydrazines or hydrazides for each of them.

On the other hand, quinones which have been simultaneously obtained by acid-splitting may be reacted with different arylhydrazines or hydra- By the action of phenylhydrazine on emulsions Serial No. 151,811.

I declare that what I claim is: 1. "The method of producing a colored image in a photographic emulsion which comprises-developing a silver salt image with a primary aromatic amino coupling developer in the presence oi a coupling component which couples with the oxidation product of said developer, treating the resulting coupled dye image with acid to split it and treating the ketonic part of the split prodconsists oi indophenols, indamines and azomethines with acid and treating the resulting carbowl-containing dye with a compound selected from the group which consists of arylhydrazines and arylhydrazides. 5. The method of producing a colored image in a photographic emulsion which comprises of elements referred to in my U. 8. application I uct with a compound selected from the group which consists of arylhydrazines and arylhydra- 'zides.

2. The method 0! producing a colored image in a photographic emulsion which comprises developing a silver salt image with a primary aromatic amino coupling developer in the presence of a coupling component consisting of an aromatic compound having a hydroxyl group on the nucleus and a carbonyl group attached to the developing a silver salt image with a primary aromatic amino coupling developer in the presence of a coupling component which couples with the oxidation product of said developer and treating the resulting coupleddye with acid in presence of a compound selected from the group which consists oi arylhydrazines and arylhydrazides.

6. The method of producing a colored image in a photographic emulsion which comprises developing a silver salt image with a primary aromatic amino coupling developer in the presence of a coupling component consisting oi an arcmatic compound having a hydroxyl' group on the nucleus and treating the, resulting coupled dye with acid in presenc of a compound selected from the group which consists of arylhydrazines and arylhydrazides.

'7. The method of producing a colored image in a photographic emulsion which comprises treating an image comprising a compound selected from the group which consists of indophenols, indamines and azomethines with acid in presence of a compound selected from the group which consists of arylhydrazines and arylhydrazides.

nucleus, treating the resulting coupled dye with acid to split it and treating the quinone part of the split product with a compound selected from the group which consists of arylhydrazines and arylhydra'zides.

3. The method of producing a colored image in a photographic emulsion which comprises developing a silver salt image with'a primary aro matic amino coupling developer in the presence 8. The method of producing a colored image in a photographic emulsion which comprises developing a silver salt image in said emulsion with a primary aromatic amino developing agent in the presence of a naphtholic coupling component, treating the resulting image dye with acid to split it and reacting the split product with a nitroarylhydrazine.

9. The method of producing a natural color image in three emulsions on a single support sensitive respectively to diflerent spectral regions and containing different-coupling components which consists in developing silver salt-images in the emulsions with primary aromatic amino coupling developers and compounds which couple with the oxidation products of said developers to produce three silver plus coupled dye images. treating the images with acid to split the coupled dyes and reacting all 01' the split dyes with the same arylhydrazine.

' KARL SCHINZEL. 

